A. Field of the Invention
The present invention relates to a method for manufacturing identification codes of integrated circuits, and more specifically, to an automatic method for manufacturing identification codes of integrated circuits.
B. Description of Related Art
Almost all of the integrated circuits (ICs), such as those applied in a hard disk, a portable flash disk and a handset, etc., contain their own identification codes. If two hard disks or portable flash disks with the same identification code are simultaneously plugged into a personal computer, they will confuse the central processor unit (CPU) and cause a crash. Further, if the identification codes on the SIM cards of two handsets are the same, it will also result in communication problems.
Generally, writing an identification code into an IC is manually done with a module or a writer. This step alone takes more than 10 seconds for each IC, which is a waste of time and labor, and also may easily cause an inattentive error.
A normal wafer testing process is shown in FIG. 1. After testing for a whole lot of normal wafers, the passed wafers are sample-tested with the following quality control (QC) test and shipped out afterward, so as to prevent un-inspected defective products from the normal lot testing or improper locations of wafers deposited by people. The wafers that do not pass the testing will be re-tested, among which the passed ones will go through the same process before shipping, and the rest will be scrapped. The conventional manner of the use of serial numbers for writing ICs would not cause any problem for the employment of normal lot testing along, i.e., each IC has its own identification code (serial number). But, if wafers of a lot are conducted with a re-testing or a QC test, the serial number is reset to zero at the initialization of the lot testing, and the serial numbers written on the ICs are possibly repeated, causing the problems of repetitive identification codes.
The object of the present invention is to prevent each IC from having the same identification code and causing confusion during the IC operation and even resulting in a tool crash or system paralysis. Moreover, the present invention can be automated to avoid manual inattention and reduce labor cost.
The present invention uses a test machine to write the number of test machine, a period of time ahead of loading a test pattern and a serial number into each IC. The present invention can ensure that the written identification code of each IC is distinct to avoid the identification problems.
The manufacturing method of identification codes for ICs of a preferred embodiment according to the present invention includes the following steps: (a) a first pattern is produced, which comprises the data of the number of a test machine for testing ICs and a period of time ahead of loading a testing pattern into the test machine; (b) a second pattern is produced, which comprises the data of serial numbers and their corresponding addresses; (c) a serial number of the second pattern for one of the ICs is extracted based on the corresponding address; and (d) the number of the test machine, the period of time ahead of loading the testing pattern and the serial number are written into the IC specified by the corresponding address as the identification code.
The above-mentioned first pattern for being extracted by the test machine and written into the ICs can be formed in the way of extracting and converting the number of the test machine and the time by a program, such as a perl language. The second pattern can be one large enough for supplying all the serial numbers required by the ICs of a whole lot of wafers to save the time of repetitive pattern loading for each of the ICs. Before the testing of each lot of wafers or the testing of the same lot of wafers for the normal lots, re-testing lots and quality control lots, the serial numbers of them need to be reset to zero.